Before he was a Broadway performer, an author, or the star of his own show, he was "Iron" Mike Tyson: the undisputed heavyweight champion at a time when that was still the most revered title in sports, one of the two most popular active athletes in the world (either narrowly ahead of or narrowly behind Michael Jordan), and, at times, a rubberneck-worthy spectacle unlike any other celebrity of his time. Tyson was, in every possible sense, a phenomenon.

'Mike Tyson: Undisputed Truth' premieres Saturday night at 8 PM on HBO, offering a deeply personal look at that phenomenon through his older, wiser, and self-described "domesticated" eyes. Before the HBO debut of his one-man show, Inside HBO Boxing offers a look at five of his most memorable fights, ones that illustrate his journey from the most feared fighter on the planet, to the loser of the most shocking upset in sports history, to a sympathetic figure and still the biggest draw in the sport more than a decade after his prime ended. The reason audiences hang on Tyson's every word now is because of the talking his fists did then.

Tyson KO 2 Trevor Berbick, November 22, 1986

A 20-year-old Tyson was seeking to fulfill his late mentor Cus D'Amato's prophecy that he would become the youngest heavyweight champion ever, challenging for his first belt against Berbick, who in his previous fight upset Pinklon Thomas for a piece of the splintered title. Tyson's 25 knockouts in 27 wins without a defeat implied remarkable power, but he hadn't yet proven it against championship-caliber opposition. By the time he'd knocked Berbick down three times with a single left hook in the second round, there wasn't much left to doubt. Normal men don't reduce heavyweight titleholders to bumbling, stumbling, yoyo-ing knockout victims like that.

Tyson KO 4 Larry Holmes, January 22, 1988

It's a boxing ritual: the rising star decimating the faded legend. In the case of the former champ Holmes, it was a 38-year-old legend who hadn't fought in nearly two years, but who had never been soundly beaten in his career; his only defeats in 50 fights were a pair of razor-thin decisions to Michael Spinks. So if 21-year-old Tyson thrashed "The Easton Assassin," it would make a statement (if a somewhat predictable one). What transpired certainly qualified as a thrashing. Tyson dominated the first three rounds, Holmes enjoyed a few seconds of recaptured youth early in round four when he bounced on his toes and popped his famous jab, and then it all unraveled—Tyson's pressure, energy, and power producing three knockdowns, the final blow a right hand that flattened Holmes in a way that no one before (or in 24 more fights after) was able to do.

Tyson KO 1 Michael Spinks, June 27, 1988

This is Tyson at his most Tyson-esque, with intimidation setting his opponent up for defeat and then two-fisted fury completing the job. Spinks was the lineal heavyweight champion, undefeated in 31 bouts, and theoretically a threat to put a dent in Iron Mike. Little did most people realize he wasn't even a threat to survive the first round. A left uppercut and a right to the body dropped Spinks. When he rose, the very next punch—another short right hand—put him down for the 10 count. With that stunningly easy, 91-second win, Tyson secured not only the undisputed title but a perception of utter invincibility.

Buster Douglas KO 10 Tyson, February 11, 1990

Forget the USA hockey team beating the Soviets or Villanova winning the NCAA title. This was the longest long shot in sports history. Coming in, Douglas, was a 42-1 underdog, and a loser to the likes of Tony Tucker, Jesse Ferguson, Mike White, and David Bey. Yet he did the unthinkable against seemingly the most devastating force heavyweight boxing had ever known. In hindsight, we all know Tyson took the fight as lightly as every fan did, and Douglas somehow fought the perfect fight nobody knew he had in him. Buster kept the shorter Tyson on the end of his jab, hammered him with flush right hands, and won round after round. Even on his worst day, Tyson almost got the job done with a miracle uppercut in the eighth round, but Douglas just barely beat the count. Two rounds later, it was over, Tyson fishing for his mouthpiece as referee Octavio Meyran counted him out, kicking off the rapid descent of an icon.

Lennox Lewis KO 8 Tyson, June 8, 2002

Incredibly, it was not until his 55th pro fight that Tyson was listed as an underdog. And even at age 35 against a future-Hall of Famer in Lewis, he was considered a live underdog because the punch is the last thing to go. In a bout that broke all pay-per-view sales records, Tyson tried for one round to connect with that punch that would make him champion again. But once the first three minutes were up, it was all Lewis. Tyson's solid chin kept him in the fight, but Lewis pounded him until finally ending matters with two knockdowns in round eight. Tyson would fight again, but never at the championship level.

Fortunately, in a heartwarming twist no one ever really imagined, Tyson has found a way to matter without stepping into the ring. He is a star of stage and screen, an author, a boxing promoter, a rededicated family man, and—dare we say it—a beloved celebrity. He was once trapped in a downward spiral, unable to escape a past about which he felt great shame. But the undisputed truth has set him free.

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